This invention relates to systems for removing solids from waste water. More specifically, it relates to apparatus for filtering out and incinerating such solids. The invention herein described was made in the course of or under Contract DOT-CG-12843-A with the U.S. Coast Guard.
Systems are known in the art for filtering solid materials from waste water, and for incinerating the resulting sludge. Such a system is described in the related application, cross-referenced above. In this system, a particulate filter bed of special, porous materials intercepts solid particles as waste water is flowed through it. Subsequently, hot, oxidizing gas is forced upwardly through the filter bed, incinerating the solid particles of waste material. U.S. Pat. No. 1,197,640 to H. Kriegsheim describes a similar, catalytic filter bed, but it cannot also be used as an incinerator. U.S. Pat. No. 3,509,835 to N. R. Dibelius, et al describes a combined filter and incinerator wherein the filter portion is a particulate bed.
The particulate beds, which comprise the filter-grates of these prior-art devices, have a number of disadvantages that are overcome by the present invention: (1) The oxidizing gas must be forced through the bed under considerable pressure, so that all parts thereof may be exposed to incineration; (2) For optimum incineration, this pressure should be variable, since considerably greater pressure is required initially, when the bed is wet and heavy with sludge; and (3) The entire filtering and incinerating process tends to be slow and wasteful of energy, because of the excessive time required for drainage, heating and cooling of the particulate bed.